Efficiency optimization method of switching power supply based on PWM control

Abstract

The present invention relates to the technical field of switching power supplies, and specifically discloses a method for optimizing the efficiency of a switching power supply based on PWM control, which solves the problems of insufficient multi-loss collaborative optimization, poor adaptability to working conditions, and low power supply efficiency in traditional technologies. The present invention performs an initial confirmation through the conduction characteristics associated with the switching power supply, and locks the frequency interval associated with the corresponding frequency value of the corresponding power supply based on the confirmed conduction characteristics and the change interval of the adaptive voltage, and then adjusts the frequency based on the corresponding frequency interval, and locks the change curve based on the specific adjustment change process, and selects the low point with the lowest loss value from the numerical change state of the three groups of change curves, and then identifies the change characteristics of the corresponding point from multiple groups of curve segments between the low points, thereby confirming the optimal frequency and executing it, ensuring that the corresponding switching power supply can meet the application power demand, and synchronously effectively optimizing the efficiency of the switching power supply.

Description

Technical Field

[0001] The present invention relates to the technical field of switching power supplies, and in particular to a method for optimizing the efficiency of a switching power supply based on PWM control. Background Art

[0002] In the field of power electronics, switching power supplies are widely used in consumer electronics, industrial control, and other scenarios due to their advantages such as high efficiency and small size. However, with the increase in power density and the growing demand for wide-operating conditions, efficiency optimization under traditional PWM control methods faces many challenges. Existing technologies generally use fixed-frequency or simple variable-frequency control, which makes it difficult to balance switching losses, conduction losses, and drive losses across the full load range. For example, when the input voltage is 12V and the output voltage needs to be adjusted between 2V and 4V, a fixed-frequency solution may cause a surge in switching losses due to a mismatch between the duty cycle and frequency, or increase conduction losses due to excessive inductor current ripple.

[0003] In addition, existing technologies lack a systematic strategy for the coordinated optimization of multiple loss curves, and often only optimize a single loss type, ignoring the coupling effect between driving loss and other losses.

[0004] For example, some solutions reduce the inductor size by increasing the switching frequency, but do not simultaneously optimize the driving circuit parameters, resulting in a sharp increase in the proportion of driving losses at high frequencies; other solutions use low on-resistance devices to reduce conduction losses, but the increase in device parasitic capacitance exacerbates the contradiction between driving losses and switching losses.

[0005] At the same time, when determining the optimal operating point, traditional methods lack quantitative analysis of the loss curve characteristics, making it difficult to accurately locate the coordinated balance point from the changing curves of switching loss, conduction loss, and driving loss, resulting in significant efficiency fluctuations in the actual operation of the power supply.

[0006] With the increasing requirements for power efficiency and reliability in new energy, consumer electronics and other fields, there is an urgent need for an efficiency optimization method that can dynamically adjust the frequency range based on the conduction characteristics and find the optimal operating point through multi-loss curve characteristic analysis. This method can solve the problems of insufficient multi-loss coordinated optimization and poor adaptability to working conditions in traditional technologies, and promote the development of switching power supplies towards high efficiency and high reliability. Summary of the Invention

[0007] In response to the shortcomings of the existing technology, the present invention provides a switching power supply efficiency optimization method based on PWM control, which solves the problems of insufficient multi-loss collaborative optimization, poor working condition adaptability, and low power supply efficiency in traditional technologies.

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions: a method for optimizing the efficiency of a switching power supply based on PWM control, comprising the following steps:

[0009] Confirm the operating voltage Vg and the adaptation voltage Sv of the switching power supply by using the ratio confirmation method: (Sv÷Vg)=Dt to confirm the current associated conduction characteristic Dt;

[0010] Based on the confirmed conduction characteristics, the frequency range associated with the current switching power supply is confirmed and adjusted in real time. The different losses generated by the switching power supply during the real-time adjustment process are confirmed. According to the frequency adjustment process, the characteristic frequency associated with the frequency and loss is locked. Then, the optimal frequency is locked based on the curve characteristics displayed between multiple groups of characteristic frequencies.

[0011] Preferably, the specific method for confirming the frequency range associated with the switching power supply is:

[0012] According to the preset voltage floating value Y1 of the adaptive voltage, a variation range of the adaptive voltage [Sv-Y1, Sv+Y1] is generated, where Y1 is the preset value;

[0013] Then, based on the variation interval [Sv-Y1, Sv+Y1], the conduction characteristics Dt1 and Dt2 associated with (Sv-Y1) and (Sv+Y1) are determined respectively, where Dt1 < Dt2. Based on the preset conduction time X1, where X1 is a preset fixed value of 1μs, the following is used: The two sets of frequency values ​​f1 and f2 associated with the turn-on characteristics Dt1 and Dt2 are locked. Since Dt1<Dt2, f1<f2, thereby confirming the frequency range [f1, f2] of the switching power supply.

[0014] Preferably, the specific form of the characteristic frequency is:

[0015] According to the frequency range [f1, f2] confirmed by the switching power supply, the switching frequency is controlled to change in value. During the switching frequency change process, the operating parameters associated with the switching power supply are monitored. Based on the monitored operating parameters, the switching loss, conduction loss, and driving loss associated with the current switching power supply are locked.

[0016] Generate switching loss change curves, conduction loss change curves, and drive loss change curves based on real-time monitored operating parameters;

[0017] The lowest loss point is locked from the switching loss change curve and used as the lowest switching loss point. The lowest conduction loss point and the lowest driving loss point associated with the conduction loss change curve and the driving loss change curve are then confirmed in turn. The frequency values ​​associated with the lowest switching loss point, the lowest conduction loss point, and the lowest driving loss point are recorded as characteristic frequencies.

[0018] Preferably, the specific method for confirming the optimal frequency is:

[0019] If the three sets of characteristic frequencies are the same, then this characteristic frequency is recorded as the optimal frequency;

[0020] If two of the three sets of characteristic frequencies are the same, then determine the numerical interval associated with the two sets of identical characteristic frequencies and the other characteristic frequency. Based on this numerical interval, lock three sets of curve segments from the three sets of change curves, and lock different loss points associated with the same frequency value from the three sets of curve segments. The loss value associated with the corresponding loss point is recorded as SY i-k , where i represents different change curves, k represents different loss points in the corresponding change curve, and the loss value associated with the adjacent loss points before and after the loss point in the same curve segment is recorded as SY1 i-k and SY2 i-k , where SY1 i-k The corresponding loss point is located at SY i-k Before the corresponding loss point, SY2 i-k The corresponding loss point is located at SY i-k After the corresponding loss point, use: JZ i-k =[(SY i-k -SY1 i-k )+(SY2 i-k -SY i-k )]÷2 confirms the mean characteristic JZ associated with the corresponding loss point i-k , using: ZH i-k =SY i-k +JZ i-k Confirm the comprehensive characteristics associated with the corresponding loss points, and sum the comprehensive characteristics of the three groups of loss points associated with the same frequency value in the three change curves to lock the total value characteristics. Confirm the total value characteristics associated with different frequency values ​​in the numerical range in turn, and select the minimum value from several total value characteristics. The frequency value associated with the minimum value is recorded as the optimal frequency.

[0021] If the three groups of characteristic frequencies are all different, the three groups of characteristic frequencies are sorted as: P1, P2, P3, and P1 < P2 < P3, then the numerical intervals [P1, P2] and [P2, P3] associated with the two groups of characteristic frequencies are determined, the curve segments associated with the numerical interval [P1, P2] are confirmed, and the total value features associated with the same frequency value are confirmed from the confirmed three groups of curve segments, and the minimum value is selected from the multiple total value features, and the frequency value associated with the minimum value is recorded as the first candidate frequency;

[0022] Reprocess the curve segment associated with the numerical interval [P2, P3], using the same confirmation method as the first candidate frequency, lock the second candidate frequency from the curve segment associated with the numerical interval [P2, P3], and confirm the two sets of total value features associated with the two sets of candidate frequencies from the first candidate frequency and the second candidate frequency. Then, select the minimum value from the two sets of total value features, and record the candidate frequency associated with the minimum value as the optimal frequency;

[0023] Based on the determined optimal frequency, the current switching power supply is operated according to the optimal frequency, and the conduction characteristics are pre-debugged during the operation process. Then, in the specific debugging process, the optimal conduction characteristics are locked and executed using the same confirmation method as the optimal frequency.

[0024] The present invention provides a method for optimizing the efficiency of a switching power supply based on PWM control. Compared with the prior art, it has the following advantages:

[0025] The present invention initially confirms the conduction characteristics associated with the switching power supply, and based on the confirmed conduction characteristics and the change range of the adaptive voltage, locks the frequency range associated with the corresponding frequency value of the corresponding power supply. Then, based on the corresponding frequency range, the frequency associated with the switching power supply is adjusted and changed. According to the specific adjustment and change process, the change curve of the corresponding loss value is locked, and the low point with the lowest loss value is selected from the numerical change states of the three groups of change curves. Then, from the multiple groups of curve segments between the low points, the change characteristics of the corresponding points are identified, thereby confirming the optimal frequency associated with the current switching power supply and executing it. Under the premise of ensuring that the corresponding switching power supply can meet the power demand of the application, the efficiency of the switching power supply is effectively optimized simultaneously.

[0026] By checking the changes in the conduction characteristics of the switching power supply and adopting the same determination method as the corresponding optimal frequency, the optimal conduction characteristics associated with the corresponding switching power supply are locked, and then the corresponding switching power supply is operated according to the optimal conduction characteristics and the optimal frequency, so as to achieve the best power efficiency optimization effect, ensure that the switching power supply can effectively reduce the loss to the minimum under the PWM control state, and achieve the overall optimization control effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of the process of the present invention. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] See also Figure 1 , the present application provides a method for optimizing the efficiency of a switching power supply based on PWM control, comprising the following steps:

[0030] Step 1: Confirm the working voltage and adaptation voltage of the switching power supply. Use the ratio confirmation method to lock the conduction characteristics associated with the specified input object of the current switching power supply. Specifically, the so-called specified input object is the corresponding working device, the specific object that needs to be powered by the switching power supply, and the working voltage of the switching power supply is its own working voltage, that is, the input voltage. Its adaptation voltage is the output voltage, that is, the corresponding voltage that the specified input object can receive. If the input voltage is 12V, the adaptation voltage that the specified input object can receive is 3V, then the input voltage needs to be compressed by a quarter. In order to achieve this processing compression method, the switching power supply confirms the on-time of the interval period. Its on-time is one-quarter of the interval period. The interval period is a single frequency period, generally 1Hz. If there are fifty interval periods in 1 second, then the switching frequency of the current switching power supply is 50Hz.

[0031] Among them, the method for confirming the conduction characteristics is:

[0032] Calibrate the operating voltage of the switching power supply as Vg, calibrate the confirmed adaptation voltage as Sv, and use: (Sv÷Vg)=Dt to confirm the current associated conduction characteristic Dt;

[0033] Step 2: Based on the confirmed conduction characteristics, the frequency range associated with the current switching power supply is confirmed and adjusted in real time. The different losses generated by the switching power supply during the real-time adjustment process are confirmed. According to the frequency adjustment process, the characteristic frequency associated with the frequency and the loss is locked. Then, based on the curve characteristics displayed between the multiple sets of characteristic frequencies, the optimal frequency is locked. Specifically, the optimal balance point is the operating state where the corresponding switching power supply is in the lowest loss state under the corresponding frequency operating state, thereby achieving the optimal operating state;

[0034] The specific method for confirming the frequency range associated with the switching power supply is as follows:

[0035] According to the preset voltage floating value Y1 of the adaptive voltage, the variation range of the adaptive voltage is generated [Sv-Y1, Sv+Y1], where Y1 is a preset value, which is prepared by the operator in advance based on experience and is generally 0.5V;

[0036] Then, based on the variation interval [Sv-Y1, Sv+Y1], the conduction characteristics Dt1 and Dt2 associated with (Sv-Y1) and (Sv+Y1) are determined respectively, where Dt1 < Dt2. Based on the preset conduction time X1, where X1 is a preset fixed value, generally determined by the operator based on experience, generally taking a value of 1μs, the following is used: Lock the two sets of frequency values ​​f1 and f2 associated with the conduction characteristics Dt1 and Dt2. Since Dt1 < Dt2, f1 < f2, this confirms the frequency range [f1, f2] of the switching power supply. Specifically, when the output voltage changes, its corresponding conduction ratio will change. Then, when the conduction time is fixed, the associated voltage frequency will also change specifically. Therefore, the frequency range associated with the corresponding power supply during the change process can be locked, which facilitates subsequent frequency adjustment.

[0037] The specific method for confirming the characteristic frequency associated with the loss is as follows:

[0038] Based on the frequency range [f1, f2] confirmed by the switching power supply, the switching frequency is controlled to change from f1 to f2 at a consistent rate (i.e., the speed of change of the value, generally 1kHz per second). During the switching frequency change process, the operating parameters associated with the current switching power supply are monitored. Based on the monitored operating parameters, the switching loss, conduction loss, and drive loss associated with the current switching power supply are locked.

[0039] Where: switching loss = switching frequency × input voltage × output current × (current single rise time + current single fall time); conduction loss = output current 2 × on-resistance; driving loss = switching frequency × total parasitic capacitance × gate-source driving voltage. The specific parameters associated with the above corresponding losses can be directly collected in the running switching power supply and are the operating parameters associated with the corresponding switching power supply.

[0040] Based on the real-time monitored operating parameters, the switching loss change curve, conduction loss change curve, and drive loss change curve are generated. The horizontal coordinate axis of the three sets of curves is the frequency change value, and the vertical coordinate axis is the loss value.

[0041] The lowest loss point is locked from the switching loss change curve and used as the lowest switching loss point. The lowest conduction loss point and the lowest driving loss point associated with the conduction loss change curve and the driving loss change curve are then confirmed in turn. The frequency values ​​associated with the lowest switching loss point, the lowest conduction loss point, and the lowest driving loss point are recorded as characteristic frequencies:

[0042] The specific method for confirming the optimal frequency associated with the current switching power supply is:

[0043] If the three sets of characteristic frequencies are the same, then this characteristic frequency is recorded as the optimal frequency;

[0044] If two of the three sets of characteristic frequencies are the same, then determine the numerical interval associated with the two sets of identical characteristic frequencies and the other characteristic frequency. Based on this numerical interval, lock the three sets of curve segments from the three sets of change curves (the frequencies associated with the endpoint values ​​of the curve segments are the endpoint values ​​of the numerical intervals). Lock the different loss points associated with the same frequency values ​​from the three sets of curve segments, and record the loss values ​​associated with the corresponding loss points as SY. i-k , where i represents different change curves, k represents different loss points in the corresponding change curve, and the loss value associated with the adjacent loss points before and after the loss point in the same curve segment is recorded as SY1 i-k and SY2 i-k , where SY1 i-k The corresponding loss point is located at SY i-k Before the corresponding loss point, SY2 i-k The corresponding loss point is located at SY i-k After the corresponding loss point, use: JZ i-k =[(SY i-k -SY1 i-k )+(SY2 i-k -SY i-k )]÷2 confirms the mean characteristic JZ associated with the corresponding loss point i-k , using: ZH i-k =SY i-k +JZ i-k Confirm the comprehensive characteristics associated with the corresponding loss points, and sum the comprehensive characteristics of the three groups of loss points associated with the same frequency value in the three change curves to lock the total value characteristics. Confirm the total value characteristics associated with different frequency values ​​in the numerical range in turn, and select the minimum value from several total value characteristics. The frequency value associated with the minimum value is recorded as the optimal frequency.

[0045] Specifically, if there are three groups of characteristic frequencies, two of which are the same, that is, P1 and P2 are the same, and P3 is different, then the corresponding numerical interval [P1 or P2, P3] can be confirmed, and the three curve segments of this numerical interval can be locked from the three changing curves. Different characteristic frequencies in each curve segment correspond to different loss points, and different loss points correspond to different loss values, and each loss point can confirm the comprehensive characteristics. A single characteristic frequency corresponds to three comprehensive characteristics. After summing them, the corresponding total value characteristics can be confirmed. Then, based on the corresponding total value characteristics, the minimum value can be specifically confirmed, thereby locking the corresponding characteristic frequency and recording it as the corresponding optimal frequency, which is convenient for subsequent efficiency optimization control.

[0046] If the three groups of characteristic frequencies are all different, the three groups of characteristic frequencies are sorted as: P1, P2, P3, and P1 < P2 < P3, then the numerical intervals [P1, P2] and [P2, P3] associated with the two groups of characteristic frequencies are determined, the curve segments associated with the numerical interval [P1, P2] are confirmed, and the total value features associated with the same frequency value are confirmed from the confirmed three groups of curve segments, and the minimum value is selected from the multiple total value features, and the frequency value associated with the minimum value is recorded as the first candidate frequency;

[0047] Reprocess the curve segment associated with the numerical interval [P2, P3], using the same confirmation method as the first candidate frequency, lock the second candidate frequency from the curve segment associated with the numerical interval [P2, P3], and confirm the two sets of total value features associated with the two sets of candidate frequencies from the first candidate frequency and the second candidate frequency. Then, select the minimum value from the two sets of total value features, and record the candidate frequency associated with the minimum value as the optimal frequency;

[0048] Specifically, when the three sets of characteristic frequencies are different, there will be two sets of numerical intervals. From the two sets of numerical intervals, the different curve segments associated with different frequency segments can be confirmed, and the characteristics of the curve segments can be verified to identify the different loss values ​​associated with the corresponding frequency points. Then, through the identified several loss values, the specific point with the optimal loss state can be locked, so that the optimal point can be specifically locked.

[0049] Step 3: Based on the determined optimal frequency, the current switching power supply is operated according to the optimal frequency, and the conduction characteristics are pre-debugged during the operation process. Then, in the specific debugging process, the optimal conduction characteristics are locked and executed. The specific method of locking the optimal conduction characteristics is:

[0050] According to the determined conduction characteristic Dt, a set of variable intervals is determined, wherein the variable intervals are [Dt-0.1Dt, Dt+0.1Dt];

[0051] Maintaining the determined optimal frequency unchanged, the conduction characteristic is varied within the variable range. Based on the specific variation process, the switching loss variation curve, the conduction loss variation curve, and the drive loss variation curve are confirmed. The optimal conduction characteristic is locked and executed within the variable range using the same determination method as the optimal frequency of the switching power supply. Subsequently, the switching power supply is controlled to operate according to the optimal conduction characteristic.

[0052] Specifically, when confirming its optimal conduction characteristic, the method is the same as the confirmation of the corresponding optimal frequency. The lowest loss point is selected from the three changing curves, and the corresponding characteristic frequency is locked through the corresponding lowest loss point. Then, based on the interval between the corresponding characteristic frequencies, the corresponding numerical interval is locked. Then, based on the multiple groups of curve segments associated with the corresponding numerical interval, the comprehensive characteristics of a single loss point and the total value characteristics associated with the corresponding frequency value are completed in turn. Then, based on the comprehensive evaluation and processing method of the corresponding total value characteristics, the optimal conduction characteristic is selected from several different conduction characteristics to achieve the optimal power efficiency optimization processing process.

[0053] Some of the data in the above formulas are dimensionless and numerically calculated. Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0054] The above embodiments are only used to illustrate the technical method of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical method of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical method of the present invention.

Claims

1. A method for optimizing the efficiency of a switching power supply based on PWM control, characterized in that: The following steps are involved: Confirm the operating voltage and adaptation voltage of the switching power supply, and use the ratio confirmation method to lock the conduction characteristics associated with the current switching power supply for the specified input object; Based on the confirmed conduction characteristics, the frequency range associated with the current switching power supply is confirmed and adjusted in real time. The different losses generated by the switching power supply during the real-time adjustment process are confirmed. Based on the frequency adjustment process, the characteristic frequency associated with the frequency and loss is locked. The specific method is as follows: According to the frequency range [f1, f2] confirmed by the switching power supply, the switching frequency is controlled to change in value. During the switching frequency change process, the operating parameters associated with the switching power supply are monitored. Based on the monitored operating parameters, the switching loss, conduction loss, and driving loss associated with the current switching power supply are locked. Generate switching loss change curves, conduction loss change curves, and drive loss change curves based on real-time monitored operating parameters; The lowest loss point is identified from the switching loss change curve and used as the lowest switching loss point. The lowest conduction loss point and the lowest driving loss point associated with the conduction loss change curve and the driving loss change curve are then confirmed in turn. The frequency values ​​associated with the lowest switching loss point, the lowest conduction loss point, and the lowest driving loss point are recorded as characteristic frequencies. The optimal frequency is then identified based on the curve characteristics displayed between multiple sets of characteristic frequencies. According to the determined optimal frequency, the current switching power supply is operated according to the optimal frequency, and the conduction characteristics are pre-debugged during the operation process. Then, from the specific debugging process, the optimal conduction characteristics are locked and executed.

2. The method for optimizing the efficiency of a switching power supply based on PWM control according to claim 1, characterized in that: The conduction characteristics are confirmed in the following manner: The operating voltage of the switching power supply is calibrated as Vg, the confirmed adaptation voltage is calibrated as Sv, and the current associated conduction characteristic Dt is confirmed using: (Sv÷Vg)=Dt.

3. The method for optimizing the efficiency of a switching power supply based on PWM control according to claim 2, characterized in that: The specific method for confirming the frequency range associated with the switching power supply is: According to the preset voltage floating value Y1 of the adaptive voltage, a variation range of the adaptive voltage [Sv-Y1, Sv+Y1] is generated, where Y1 is the preset value; Then, based on the variation interval [Sv-Y1, Sv+Y1], the conduction characteristics Dt1 and Dt2 associated with (Sv-Y1) and (Sv+Y1) are determined respectively, where Dt1 < Dt2. Based on the preset conduction time X1, where X1 is a preset fixed value of 1μs, the following is used: The two sets of frequency values ​​f1 and f2 associated with the turn-on characteristics Dt1 and Dt2 are locked. Since Dt1<Dt2, f1<f2, thereby confirming the frequency range [f1, f2] of the switching power supply.

4. The method for optimizing the efficiency of a switching power supply based on PWM control according to claim 1, wherein: The specific method for confirming the optimal frequency associated with the switching power supply is: If the three sets of characteristic frequencies are the same, then this characteristic frequency is recorded as the optimal frequency.

5. The method for optimizing the efficiency of a switching power supply based on PWM control according to claim 4, characterized in that: If two of the three sets of characteristic frequencies are the same, then determine the numerical interval associated with the two sets of identical characteristic frequencies and the other characteristic frequency. Based on this numerical interval, lock three sets of curve segments from the three sets of change curves, and lock different loss points associated with the same frequency value from the three sets of curve segments. The loss value associated with the corresponding loss point is recorded as SY i-k , where i represents different change curves, k represents different loss points in the corresponding change curve, and the loss value associated with the adjacent loss points before and after the loss point in the same curve segment is recorded as SY1 i-k and SY2 i-k , where SY1 i-k The corresponding loss point is located at SY i-k Before the corresponding loss point, SY2 i-k The corresponding loss point is located at SY i-k After the corresponding loss point, use: JZ i-k =[(SY i-k -SY1 i-k )+(SY2 i-k -SY i-k )]÷2 confirms the mean characteristic JZ associated with the corresponding loss point i-k , using: ZH i-k =SY i-k +JZ i-k Confirm the comprehensive characteristics associated with the corresponding loss points, and sum the comprehensive characteristics of the three groups of loss points associated with the same frequency value in the three change curves to lock the total value characteristics. Confirm the total value characteristics associated with different frequency values ​​in the numerical range in turn, and select the minimum value from several total value characteristics. The frequency value associated with the minimum value is recorded as the optimal frequency.

6. The method for optimizing the efficiency of a switching power supply based on PWM control according to claim 5, characterized in that: If the three groups of characteristic frequencies are all different, the three groups of characteristic frequencies are sorted as: P1, P2, P3, and P1 < P2 < P3, then the numerical intervals [P1, P2] and [P2, P3] associated with the two groups of characteristic frequencies are determined, the curve segments associated with the numerical interval [P1, P2] are confirmed, and the total value features associated with the same frequency value are confirmed from the confirmed three groups of curve segments, and the minimum value is selected from the multiple total value features, and the frequency value associated with the minimum value is recorded as the first candidate frequency; The curve segment associated with the numerical interval [P2, P3] is reprocessed, and the same confirmation method as the first candidate frequency is used to lock the second candidate frequency from the curve segment associated with the numerical interval [P2, P3]. The two groups of total value features associated with the two groups of candidate frequencies are confirmed from the first candidate frequency and the second candidate frequency. The minimum value is then selected from the two groups of total value features, and the candidate frequency associated with the minimum value is recorded as the optimal frequency.

7. The method for optimizing the efficiency of a switching power supply based on PWM control according to any one of claims 4 to 6, characterized in that: The specific method of locking the optimal conduction characteristic is: According to the determined conduction characteristic Dt, a set of variable intervals [Dt-0.1Dt, Dt+0.1Dt] is determined; The determined optimal frequency is maintained unchanged, and the conduction characteristic is changed within the variable range. According to the specific change process, the switching loss change curve, the conduction loss change curve, and the driving loss change curve are confirmed. The same determination processing method of the optimal frequency of the switching power supply is adopted to lock the optimal conduction characteristic from the variable range and execute it. Subsequently, the switching power supply is controlled to operate according to this optimal conduction characteristic.

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